题目：
Walmart, which is one of the largest American supermarket chains, some of its store open 24 hours on Mondays through Saturdays.
A．keeps
B．keep
C．have kept
D．had kept
答案：
答案：A
考查动词时态。主语是“Walmart沃尔玛”为单数，故排除BC选项。根据时间状语on Mondays through Saturdays推断不可能用过去完成时。故选A。根据 24 hours on Mondays through Saturdays 可知 沃尔玛一周 7 天 24 小时开放，所以表达的应该是客观的事实，所以选一般现在时。
